Method of removing residual corrosive compounds by plasma etching followed by washing

ABSTRACT

A sample is plasma etched and then treated with a second plasma to remove residual corrosive compounds formed by the etching plasma. Removal of the residual corrosive compounds and prevention of corrosion is improved by washing the surface of the sample after the second plasma treatment with at least one liquid in order to effect at least one of (a) removal of the residual corrosive compounds and (b) passivation of the surface, the step of washing is followed by drying the sample.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of processing a sample including anetching step, and to an apparatus for carrying out such a method, andmore particularly to a processing method and apparatus which is suitablefor processing a sample in the manufacture of a semiconductor device orother device including miniaturized components.

2. Description of the Prior Art

A sample such as a semiconductor device substrate is etched by achemical solution or by plasma, for example. Sufficient care must bepaid to corrosion protection of the sample after etching processing.

A corrosion-proofing technique after etching is disclosed, for example,in U.S. Pat. No. 4,487,678. This prior art technique subjects a resistfilm, after etching by plasma inside an etching chamber, to removal in asecond plasma processing chamber connected to the etching chamber. Thesecond plasma treatment removes chlorine compounds which are corrosivecomponents remaining in the resist film or on the etched surface. It isalso known to heat the sample after etching to at least 200° C. in orderto promote evaporation of chlorides that are residual corrosivecomponents. Japanese Laid-Open Patent Publication No. JP-A-61133388discloses a method in which a sample after plasma etching is transferredto a heat-treating chamber in which hot air is blown on it to removecorrosive compounds. Thereafter the sample is washed with water anddried.

The present applicants have found that these prior art techniquesinvolve the problem that sufficient corrosion-proofing performancecannot be obtained, at least for certain kinds of samples.

For instance, the techniques described above are believed effective insome cases for corrosion-proofing of a single metallic film such as analuminum (Al) wiring film. However, they fail to provide a sufficientcorrosion-proofing effect after etching of a sample having metals havingmutually different ionization tendencies such as films of Al, Cu, W, Ti,Mo, etc. and their alloys or laminates.

With the remarkable progress in miniaturization in recent years, wiringfilms have been more and more miniaturized, and an Al-Cu-Si alloy filmhaving a few percent of Cu content in place of the conventional Al-Sialloy film and a laminate structure of the Al-Cu-Si alloy film and arefractory metal film such as titanium tungsten (TiW), titanium nitride(TiN) and molybdenum silicon (MoSi) film for reducing contact resistancehave gained wide application as a wiring film in order to preventbreakage due to electromigration and stress migration. In such a wiringfilm structure, ionization tendencies of Al and Cu, W, Ti, Mo or thelike are different so that a kind of battery action develops due to awater component as a medium and corrosion of the wiring film isaccelerated by so-called "electrolytic corrosion". Even if corrosivematerials generated by etching are removed by utilizing plasma at a hightemperature of 200° C. or above, corrosion occurs due to the effect ofmoisture on remaining corrosive compounds within some minutes or severalhours after the sample is withdrawn into the atmosphere.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a sample processingmethod and apparatus which can prevent sufficiently corrosion of asample after etching irrespective of the kind of sample.

In one aspect, the invention provides a method of processing a samplecomprising the steps:

(i) etching the sample by means of an etching plasma, especially anetching plasma formed using a chlorine-containing gas (i.e. a gascontaining chlorine gas itself or chlorine compounds),

(ii) after step (i), treating the sample by means of a second plasma toremove residual corrosive compounds formed in step (i), said secondplasma being formed in a gas atmosphere different from that of theetching plasma,

(iii) contacting the surface of the sample exposed by steps (i) and (ii)with at least one liquid in order to effect at least one of (a) removalof residual corrosive compounds from step (i) and (b) passivation ofsaid surface exposed by steps (i) and (ii), and

(iv) after step (iii), drying the sample.

As discussed further below, it has surprisingly been found that thecombination of steps (ii) and (iii) provides remarkably improvedcorrosion resistance of a plasma-etched sample.

Where the sample is etched through a mask, the treatment of step (ii)may effect removal of at least part of the mask. The plasma of step (ii)is preferably formed in an oxygen gas atmosphere.

Preferably washing in step (iii) is selected from

(a) washing with water,

(b) washing first with an alkaline liquid and then with water,

(c) washing first with an acidic liquid and then with water, and

(d) washing first with a mixture of nitric acid and hydrofluoric acidand then with water.

Suitably, to avoid contact with air, step (iii) is performed in an inertgas atmosphere. Likewise, step (iv) may be performed in an inert gasatmosphere.

In particular the invention is applicable when a layer which issubjected to the etching of step (i) is (a) a laminate comprising metalsof different ionization potentials or (b) an alloy of metals ofdifferent ionization potentials. More generally, the etched layer may beselected from films made of Al, Cu, W, Ti, Mo, other refractory metals,alloys thereof (including alloys containing Si), silicides of refractorymetals, TiN and TiW and laminates of at least two such films.

In another aspect, the invention provides apparatus for processing asample, comprising

(i) means for effecting plasma etching of the sample, including supplymeans adapted to supply a first plasma-forming gas for the plasmaetching,

(ii) means for effecting plasma treatment of the sample after the plasmaetching, including supply means for supplying a second plasma-forminggas for the plasma treatment, said second gas being different from saidfirst gas,

(iii) means for contacting the surface of the sample exposed by theplasma etching and the plasma treatment with a liquid adapted to effectat least one of (a) removal of residual corrosive compounds formed inthe plasma etching and (b) passivation of said surface, and

(iv) means for drying said sample following contact with said liquid.

Preferably the means for plasma etching is a magnetic field-typemicrowave plasma etching apparatus, and the means for the subsequentplasma treatment is a non-magnetic field-type microwave plasma etchingapparatus.

The apparatus may comprise first and second units which are detachablefrom each other. The first unit includes the plasma etching means andthe means for plasma treatment, while the second unit includes the meansfor contacting with liquid and the drying means. The apparatus furtherincludes means for transfer of a sample from said first unit to saidsecond unit, preferably mounted on said second unit.

Preferably a sample receiving station for receiving a sample to beprocessed and a sample discharge station for discharging a sample afterthe processing are on the same side of the apparatus.

In another aspect, the invention provides a sample etching apparatuscomprising:

(i) a first plasma chamber for performing plasma etching on sample,

(ii) means for creating an etching plasma in the first plasma chamber,

(iii) a loading chamber adjacent the first plasma chamber,

(iv) a second plasma chamber for performing plasma treatment of thesample after etching in the first plasma chamber,

(v) means for forming a plasma in the second plasma chamber,

(vi) an unloading chamber adjacent the second plasma chamber,

(vii) a first rotating arm for effecting transfer of the sample fromsaid loading chamber into said first plasma chamber, and

(viii) a second rotating arm for effecting transfer of the sample fromthe first plasma chamber to the second plasma chamber and from thesecond plasma chamber to the unloading chamber,

whereby the sample is carried by said rotating arms along a path fromsaid loading chamber to said unloading chamber.

The rotating arms may rotate in a common plane.

In this description, the plasma treatment step after etching is calledpost-processing, the liquid treatment step is called wet-processing andthe drying step is called dry-processing, for convenience.

In the invention, therefore, a sample is etched by use of plasma. Afteretching, the sample is post-processed by plasma post-processing means byutilizing plasma under a reduced pressure. The post-processed samplefrom the plasma post-processing means is wet-processed by wet-processingmeans. The wet-processed sample is dry-processed by dry-processingmeans. Since post-processing using plasma and wet-processing are bothcarried out, the corrosive materials that occur due to etching can beremoved sufficiently from the etched sample. Therefore, even when theetched sample is withdrawn into external air, for example, its corrosioncan be sufficiently prevented irrespective of the kind of sample.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described below by way ofnon-limitative example with reference to the accompanying drawings, inwhich:

FIG. 1 is a block diagram of a sample processing apparatus in accordancewith one embodiment of the present invention;

FIG. 2 is a diagrammatic plan view of the apparatus of FIG. 1;

FIG. 3 is a diagrammatic longitudinal side view of the apparatus shownin FIG. 2;

FIGS. 4A-4G illustrate details of structure and operation of one part ofthe apparatus of FIGS. 2 and 3;

FIGS. 5A and 5B illustrate details of structure and operation of asecond part of the apparatus of FIGS. 2 and 3;

FIG. 6 is a sectional view showing an example of a sample;

FIG. 7 is a perspective view showing an example of occurrence ofcorrosion;

FIG. 8 is a diagram showing the relation between processing modes afteretching and the time till occurrence of corrosion; and

FIG. 9 is a block diagram of a sample processing apparatus in accordancewith a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, the sample processing apparatus includes a processingapparatus 10 for etching a sample, a plasma post-processing apparatus20, a wet-processing apparatus 30 and a dry-processing apparatus 40 andis equipped at least with means 50, 60, 70 for transferring the samplebetween these processing apparatuses.

In FIG. 1, an apparatus for processing, such as etching, the sample byutilizing plasma under a reduced pressure is used as the processingapparatus 10. Examples of the plasma etching apparatuses which may beemployed are a plasma etching apparatus, a reactive sputter etchingapparatus, a non-magnetic field type microwave plasma etching apparatus,a magnetic field type microwave plasma etching apparatus, an electroncyclotron resonance (ECR) type microwave plasma etching apparatus, aphoto-excitation plasma etching apparatus, a neutral particle etchingapparatus, and the like. Besides the apparatuses described above, it ispossible to employ an apparatus which wet-etches the sample and anapparatus which etches the sample by use of a corrosive gas.

In FIG. 1, the plasma post-processing apparatus 20 post-processes, suchas ashes (i.e. removes photoresist by oxidation), the processed sampleprocessed by the processing apparatus 10 by utilizing plasma under areduced pressure. Examples of the ash-processing apparatuses which maybe employed are a plasma ashing apparatus, non-magnetic field type andmagnetic field type microwave plasma ashing apparatuses, an ECR typemicrowave plasma ashing apparatus, a photo-excitation plasma ashingapparatus, and the like.

In FIG. 1, the wet-processing apparatus 30, such as a spinningwet-processing apparatus, wet-processes the post-processed sample fromthe plasma post-processing apparatus 20. In the spinning wet-processingapparatus, the post-processed sample is subjected to spinning washingwith water, for example, or to spinning washing sequentially withchemical solutions and water. In this case, the chemical solution isselected suitably in accordance with the materials to be removed fromthe post-processed sample. An inert gas atmosphere such as nitrogen gasor an atmospheric atmosphere is used as the processing atmosphere.Dry-processing such as water removal is sometimes conducted under thisstate after wet-processing.

In FIG. 1, an apparatus for dry-processing the wet-processed sample fromthe wet-processing apparatus 30, such as an apparatus for heating anddrying the wet-processed sample or an apparatus for blowing a dry gas onthe wet-processed sample to dry it, is used as the dry-processingapparatus 40. A nitrogen gas atmosphere or atmospheric atmosphere isused as the processing atmosphere.

In FIG. 1, the sample transfer means 50 has the function of transferringthe processed sample between a processing station (not shown) of theprocessing apparatus 10 and a processing station (not shown) of theplasma post-processing apparatus 20. The sample transfer means 60 hasthe function of transferring the post-processed sample between aprocessing station (not shown) of the plasma post-processing apparatus20 and a processing station (not shown) of the wet-processing apparatus30. The sample transfer means 70 has the function of transferring thewet-processed sample between a processing station of the wet-processingapparatus 30 and a processing station (not shown) of the dry-processingapparatus 40. The sample transfer means 50 can deliver and receive thesample between the processing station of the processing apparatus 10 andthat of the plasma post-processing apparatus 20. The sample transfermeans 60 can deliver and receive the sample between the processingstation of the plasma post-processing apparatus 20 and that of thewet-processing apparatus 30. The sample transfer means 70 can deliverand receive the sample between the processing station of thewet-processing apparatus 30 and that of the dry-processing apparatus 40.Known transfer means are used as the sample transfer means 50, 60, 70.Examples of such means include an arm conveyor equipped with samplescooping members that pick up and hold the sample which are rotated orreciprocated mechanically, electrically or magnetically, or with samplegrippers or sample adsorbers that grip and hold the sample at theirouter peripheral edge by electromagnetic adsorption or vacuumadsorption, for example, a belt conveyor having an endless belt spreadbetween a driving roller and a driven roller, an apparatus fortransferring the sample by blow force of gas, and the like. If theprocessing apparatus 10 is the apparatus which processes the sample byutilizing plasma under a reduced pressure, the sample transfer means 50is disposed in such a manner that the processed sample can betransferred inside a reduced pressure space without being exposed to theexternal air.

In this case, there are shown disposed in FIG. 1 the sample transfermeans 80 which transfers the sample to be processed by the processingapparatus 10 thereto and the sample transfer means 90 for transferringthe sample dry-processed by the dry-processing apparatus 40 to arecovery cassette (not shown), for example. Sample transfer meansanalogous to the sample transfer means 50, 60 are used as these sampletransfer means 80 and 90.

If the processing apparatus 10 in FIG. 1 processes the sample byutilizing plasma under a reduced pressure, for example, the sampleprocessing atmosphere of the processing apparatus 10 can be put incommunication with, and cut off from, the space in which the sample tobe processed by the processing apparatus 10 is transferred thereto andthe space in which the processed sample is transferred. The sampleprocessing atmosphere of the plasma post-processing apparatus 20, thespace in which the processed sample is transferred and the space inwhich the post-processed sample is transferred can be put incommunication with, and cut off from, one another. The space in whichthe post-processed sample is transferred, the sample wet-processingatmosphere of the wet-processing apparatus 30, the space in which thewet-processed sample is transferred, the sample dry-processingatmosphere of the dry-processing apparatus 40 and the space in whichdry-processed sample is transferred may be maintained in communicationwith one another or may be put in communication with, and cut off from,one another.

In FIG. 1, the processing station is disposed in the sample processingatmosphere of the processing apparatus 10. If the sample processingapparatus 10 processes the sample by utilizing plasma under a reducedpressure, the processing station is a sample table (not shown). Thesample table (not shown) is disposed as the processing station in eachof the processing atmosphere of the plasma post-processing apparatus 20,the wet-processing apparatus 30 and the dry-processing apparatus 40. Oneor a plurality of samples can be put on each sample table. In theprocessing apparatus 10 and in the plasma post-processing apparatus 20,each sample table is sometimes used as one of the constituent elementsforming the sample processing atmosphere.

An embodiment of the present invention will be explained in furtherdetail with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, an apparatus for processing the sample by utilizingplasma under a reduced pressure is used as the processing apparatus inthis case.

In FIGS. 2 and 3, four openings 101a, 101b, 101c and 101d are formed inthe top wall of a buffer chamber 100. An exhaust nozzle 102a is disposedon the bottom wall of the buffer chamber 100. One of the ends of anexhaust pipe (not shown) is connected to the exhaust nozzle 102a and itsother end, to a suction port of an evacuation apparatus (not shown) suchas a vacuum pump. The planar shape of the buffer chamber 100 issubstantially L-shaped. The buffer chamber 100 is made of a stainlesssteel in this case. When the buffer chamber 100 is viewed on a planview, the openings 101a, 101b, 101c are formed from the major side tominor side of the L shape and the opening 101d is formed on the minorside of the L shape. The openings 101a-101d have predetermined gapsbetween the adjacent pairs of them. An arm 81 is disposed rotatablyinside the buffer chamber 100. The arm 81 can rotate in one plane in thebuffer chamber 100. A sample scooping member 82 is disposed at therotating end of the arm 81. The sample scooping member 82 has shapedelements opposed in a plane. The orbit of rotation substantially at thecenter of the sample scooping member 82 is positioned in such a manneras to substantially correspond to the center of each opening 101a, 101b.In other words, the support point of rotation of the arm 81 ispositioned so that almost the center of the sample scooping member 82describes the orbit of rotation described above. The support point ofrotation of the arm 81 is positioned at the upper end of a rotary shaft83 whose upper end projects at that position into the buffer chamber100, whose lower end projects outside the buffer chamber 100 and whichis disposed rotatably on the bottom wall of the buffer chamber 100 whilekeeping air-tightness. The lower end of the rotary shaft 83 is connectedto rotation driving means (not shown) which is disposed outside thebuffer chamber 100 in such a manner as to correspond to the bottom wallof the buffer chamber 100. An arm 51 is disposed rotatably inside thebuffer chamber 100 at a position different from that of the arm 81 andon the opposite side of the sample path. The arm 51 can rotate in thesame plane in the buffer chamber 100 as the arm 81. A sample scoopingmember 52 is disposed at the rotating end of the arm 51. The planarshape of the sample scooping member 52 is substantially the same as thatof the sample scooping member 82. The arm 51 is disposed in such amanner that the orbit of rotation at the center of the sample scoopingmember 52 corresponds substantially to the center of each opening 101b,101c, 101d. In other words, the support point of rotation of the arm 51is positioned at such a position where almost the center of the samplescooping member 52 describes the orbit of rotation described above. Thesupport point of rotation of the arm 51 is positioned at the upper endof a rotary shaft 53 which is disposed rotatablY on the bottom wall ofthe buffer chamber 100 while keeping air-tightness inside the bufferchamber 100 with its upper end projecting at that position into thebuffer chamber 100 and with its lower end projecting outside the bufferchamber 100. The lower end of the rotary shaft 53 is connected to adriving shaft of rotation driving means disposed outside the bufferchamber 100 so as to correspond to the bottom wall of the buffer chamber100, such as a driving shaft of a motor 54.

In FIG. 3, a sample table 110 and a cover member 111 are disposed insuch a manner as to interpose the opening 101a between them. The sampletable 110 has a sample disposition surface on its surface. The planarshape and size of the sample table 100 are such that they can close theopening 101a. The sample table 110 is disposed inside the buffer chamber100 in such a manner as to be capable of opening and closing the opening101a and in this case, capable of moving up and down.

An elevation shaft 112 has its center of axis at the center of theopening 101a with its upper end projecting into the buffer chamber 100and with its lower end projecting outside the same and is disposed onthe bottom wall of the buffer chamber 100 in such a manner that it canmove up and down while keeping air-tightness inside the buffer chamber100. The sample table 110 is disposed substantially horizontally at theupper end of the elevation shaft 112 with its sample disposition surfacebeing the upper surface. The lower end of the elevation shaft 112 isconnected to elevation driving means, such as a cylinder rod of acylinder 113, which is disposed outside the buffer chamber 100 in such amanner as to correspond to the bottom wall of the latter. A seal ring(not shown) is disposed around the outer periphery of the upper surfaceof the sample table 110 or the inner surface of the top wall of thebuffer chamber 100 opposed to the former, that is, on the inner surfaceof the top wall of the buffer chamber 100 around the opening 101a.

A sample delivery member (not shown) is disposed on the sample table110. The sample delivery member is disposed in such a manner as to becapable of moving up and down between a position lower than the sampledisposition surface of the sample table 110 and a position whichprojects outward from the opening 101a when the opening 101a is closedby the sample table 110. The planar shape and size of the cover member111 are such that they can close the opening 101a. The cover member 111is disposed outside the buffer chamber 100 in such a manner as to becapable of opening and closing the opening 101a and in this case,capable of moving up and down. In this case, an elevation shaft 114 isdisposed outside the buffer chamber 100 in such a manner as to becapable of moving up and down with its axis being substantially inconformity with that of the elevation shaft 112. The cover member 111 isdisposed substantially horizontally at the lower end of the elevationshaft 114. The upper end of the elevation shaft 114 is connected toelevation driving means, such as a cylinder rod of a cylinder 115, whichis disposed above the cover member 111 outside the buffer chamber 100.

A seal ring (not shown) is disposed around the outer periphery of thelower surface of the cover member 111 or the outer surface of the topwall of the buffer chamber 100 opposed to the former, or in other words,around the outer surface of the top wall of the buffer chamber 100around the opening 101a. The sample table 110 and the cover member 111are thus doors of an entry airlock of the buffer chamber 100.

A discharge tube 11, whose shape is substantially semi-spherical in thiscase, is shown disposed hermetically on the top wall of the bufferchamber 100 in FIG. 3. The shape and size of the opening of thedischarge tube 11 are substantially the same as those of the opening101b, and the opening of the discharge tube 11 is substantially inagreement with the opening 101b. The discharge tube 11 is made of anelectric insulator such as quartz. A waveguide 12a is disposed outsidethe discharge tube 11 to surround it. A magnetron 13 as microwaveoscillation means and the waveguide 12a are connected by a waveguide12b. The waveguides 12a and 12b are made of an electric conductor. Thewaveguide 12b has an isolator 12c and a power monitor 12d. A solenoidcoil 14 as magnetic field generation means is disposed outside andaround the waveguide 12b.

A sample table 15 is disposed movably up and down inside the spacedefined inside the buffer chamber 100 and the discharge tube 11. Theaxis of an elevation shaft 16 is substantially in agreement with theaxis of the discharge tube 11 in this case. The elevation shaft 16 isdisposed on the bottom wall of the buffer chamber 100 movably up anddown with its upper end projecting into the buffer chamber 100 and withits lower end projecting outside the buffer chamber 100 while keepingair-tightness inside the buffer chamber 100.

More details of this part of the apparatus are given in FIGS. 5A and 5B,to which reference should be made also.

The sample table 15 has a sample disposition surface on its surface. Theplanar shape and size of the sample table 15 are such that the sampletable 15 can penetrate through the opening 101b. The sample table 15 isdisposed substantially horizontally at the upper end of the elevationshaft 16 with its sample disposition surface being its upper surface.The lower end of the elevation shaft 16 is connected to elevationdriving means, such as a cylinder rod of a cylinder (not shown), whichis disposed outside the buffer chamber 100 in such a manner as tocorrespond to the bottom wall of the same. In this case, the lower endportion of the elevation shaft 16 is connected to a bias power source,for example, a radio frequency power source 18. The radio frequencypower source 18 is disposed outside the buffer chamber 100 and isgrounded. In this case, the sample table 15 and the elevation shaft 16are in an electrically connected state but the buffer chamber 100 andthe elevation shaft 16 are electrically isolated.

A sample delivery member 15a (FIG. 5A) is disposed on the sample table15. The sample delivery member 15a is disposed at a position below thesample disposition surface of the sample table 15 and in such a manneras to be capable of moving up and down with respect to the samplescooping members 82, 52 when the sample disposition surface of thesample table 15 is moved down below the sample scooping member 82 of thearm 81 and the sample scooping member 52 of the arm 51.

The sample table 15 has means for control of the temperature. A heatmedium flow path is defined inside the sample table 15, for example, anda cooling medium as a heat medium such as cooling water, liquid ammonia,liquid nitrogen, or the like, or a heating medium such as heating gas issupplied to the flow path. Heat generation means such as a heater, forexample, is disposed on the sample table 15.

Flanges 120 and 121 are disposed around the sample table 15 and theelevation shaft 16 inside the buffer chamber 100. The inner diameter andshape of each flange 120, 121 are substantially in conformity with thoseof the opening 101b. The flange 120 is disposed air-tight on the innersurface of the bottom wall of the buffer chamber 100 with the axis ofthe elevation shaft 16 being substantially at its center. The flange 121is disposed in such a manner as to oppose the flange 120. Metallicbellows 122 a extension-contraction cut means are disposed in such amanner as to bridge these flanges 120 and 121.

An elevation shaft 122a is disposed movably up and down with its upperend projecting into the buffer chamber 100 and with its lower endprojecting outside the buffer chamber 100 while keeping air-tightnessinside the buffer chamber 100. The flange 121 is connected to the upperend of the elevation shaft. The lower end of the elevation shaft isconnected to elevation driving means such as a cylinder rod of acylinder (not shown) disposed outside the buffer chamber 100 in such amanner as to correspond to the bottom wall of the buffer chamber 100.

A seal ring is disposed on the upper surface of the flange 121 or theinner surface of the top wall of the buffer chamber 100 opposing theformer, or in other words, on the inner surface of the top wall of thebuffer chamber 100 around the opening 101b.

An exhaust nozzle 102b is disposed on the bottom wall of the bufferchamber 100 more inward than the flange 120. One of the ends of anexhaust pipe (not shown) is connected to the exhaust nozzle 102b and itsother end, to the suction port of an evacuation apparatus (not shown)such as a vacuum pump. A switch valve (not shown) and a pressureregulating valve such as a variable resistance valve (not shown) aredisposed in the exhaust pipe. One of the ends of a gas introduction pipe(not shown) is connected to a processing gas source (not shown) and itsother end opens into the discharge tube 11, or the like. A switch valveand a gas flow rate regulator (not shown) are disposed in the gasintroduction pipe.

In FIG. 3, the plasma post-processing chamber 21 is hermeticallydisposed on the top wall of the buffer chamber 100. The shape and sizeof the opening of the plasma post-processing chamber 21 aresubstantially in agreement with those of the opening 101c and theopening of the plasma post-processing chamber 21 is substantially inagreement with the opening 101c. A sample table 22 is disposed in thespace defined by the interior of the buffer chamber 100 and that of theplasma post-processing chamber 21. A support shaft 23 in this case usesthe axis of the plasma post-processing chamber 21 as its axis. It isdisposed on the bottom wall of the buffer chamber 100 with its upper endprojecting into the buffer chamber 100 and with its lower end projectingoutside the buffer chamber 100 while keeping air-tightness inside thebuffer chamber 100.

The sample table 22 has a sample disposition surface on its surface. Theplanar shape and size of the sample table 22 are smaller than those ofthe opening 101c in this case. The sample table 22 is disposedsubstantially horizontally at the upper end of the support shaft 23 withits sample disposition surface being the upper surface. The sampledisposition surface of the sample table 22 is positioned below thesample scooping member 52 of the arm 51.

A sample delivery member (not shown) is disposed on the sample table 22.In other words, the sample delivery member is disposed movably up anddown between a position lower than the sample disposition surface of thesample table 22 and a position higher than the sample scooping member 52of the arm 51.

Flanges 125 and 126 are disposed outside the sample table 22 and thesupport shaft 23 but inside the buffer chamber 100. The inner diameterand shape of each flange 125, 126 are substantially in conformity withthose of the opening 101c. The flange 125 is disposed hermetically onthe inner surface of the bottom wall of the buffer chamber 100substantially coaxial with the axis of the support shaft 23. The flange126 opposes the flange 125. Metallic bellows 127 asextension-contraction cut means bridge between these flanges 125 and126. An elevation shaft (not shown) is disposed movably up and down onthe bottom wall of the buffer chamber 100 with its upper end projectinginto the buffer chamber 100 and with its lower end projecting outsidethe buffer chamber 100 while keeping air-tightness inside the bufferchamber 100.

The flange 126 is connected to the upper end of the elevation shaft. Thelower end of the elevation shaft is connected to elevation driving meanssuch as a cylinder rod of a cylinder (not shown) which is disposedoutside the buffer chamber 100 so as to correspond to the bottom wall ofthe buffer chamber 100. A seal ring (not shown) is disposed on the uppersurface of the flange 126 or the inner surface of the top wall of thebuffer chamber 100 opposing the upper surface of the flange 126, or inother words, on the inner surface of the top wall of the buffer chamber100 around the opening 101c. An exhaust nozzle 102c is disposed on thebottom wall of the buffer chamber 100 which is more inward than theflange 125. One of the ends of an exhaust pipe (not shown) is connectedto the exhaust nozzle 102c and its other end, to the suction port of anevacuation apparatus (not shown) such as a vacuum pump.

In FIG. 3, a sample table 130 and a cover member 131 are disposed insuch a manner as to interpose the opening 101d between them. This partof the apparatus and its operation are shown in more detail in FIGS.4A-G, to which reference should be made also. The sample table 130 has asample disposition surface on its surface. The planar shape and size ofthe sample table 130 are such that the sample table 130 can sufficientlyclose the opening 101d. The sample table 130 is disposed movably up anddown, in this case, inside the buffer chamber 100 in such a 101d. Inthis case, an elevation shaft 132 is disposed movably up and down on thebottom wall of the buffer chamber 100 with its upper end projecting intothe buffer chamber 100 and with its lower end projecting outside thebuffer chamber 100 while keeping air-tightness inside the buffer chamber100. The sample table 130 is disposed substantially horizontally at theupper end of the elevation shaft 132 with its sample disposition surfacebeing the upper surface. The lower end of the elevation shaft 132 isconnected to elevation driving means such as a cylinder rod of acylinder 133 which is disposed outside the buffer chamber 100 in such amanner as to correspond to the bottom wall of the buffer chamber 100.

A seal ring is disposed around the outer peripheral edge of the uppersurface of the sample table 130 (as shown) or the inside of the top wallof the buffer chamber 100 opposing the outer peripheral edge, that is,on the inner surface of the top wall of the buffer chamber 100 aroundthe opening 101d. A sample delivery member 130a is disposed on thesample table 130. It is disposed movably up and down between a positionlower than the sample disposition surface of the sample table 130 and aposition projecting outward from the opening 101d under the state wherethe opening 101d is closed by the sample table 130.

The planar shape and size of a cover member 131 are such that the covermember 131 can open and close the opening 101d. It is disposed movablyup and down, in this case, outside the buffer chamber 100. The axis ofan elevation shaft 134 is substantially in agreement with that of theelevation shaft 132, in this case. This elevation shaft 134 is disposedmovably up and down outside the buffer chamber 100. The cover member 131is disposed substantially horizontally at the lower end of the elevationshaft 134. The upper end of the elevation shaft 134 is connected toelevation driving means such as a cylinder rod of a cylinder 135 whichis disposed at a position above the cover member 131 outside the bufferchamber 100. A seal ring is disposed around the outer peripheral edge ofthe lower surface of the cover member 131 (as shown) or the outersurface of the top wall of the buffer chamber 100 opposing the former,that is, the outer surface of the top wall of the buffer chamber 100around the opening 101d. The sample table 130 and the cover member 131thus constitute doors of an exit airlock for the buffer chamber 100.

A cassette table 140 is disposed movably up and down in such a manner asto correspond to the side surface of the L-shaped major side of thebuffer chamber 100 outside the buffer chamber 100. A guide 141 isdisposed outside the buffer chamber 100 in such a manner as to extendlinearly along the side surface of the L-shaped major side in itstransverse direction. The edge of this guide 141 on the side of thecassette table 140 is extended so as to correspond to the center of thecassette table 140, in this case. An arm 142 is a linear member in thiscase, and one of its ends is disposed on the guide 141 in such a manneras to be capable of reciprocation while being guided by the guide 141. Asample scooping member 143 is disposed at the other end of the arm 142.The cassette table 140 is disposed substantially horizontally at theupper end of an elevation shaft 144 with a cassette disposition surfacebeing its upper surface. The lower end of the elevation shaft 144 isconnected to elevation driving means 145.

The wet-processing chamber 31, the dry-processing chamber 41 and asample recovery chamber 150 are disposed outside the buffer chamber 100,in this case. They form a unit connectable to and disconnectable fromthe buffer chamber unit. The wet-processing chamber 31, thedry-processing chamber 41 and the sample recovery chamber 150 arealigned sequentially along the side walls on the side of the openings101c, 101d of the buffer chamber 100 in this case. Among them, thewet-processing chamber 31 is disposed at the position closest to theopening 101d.

A sample table 32 is disposed inside the wet-processing chamber 31. Asupport shaft 33 is disposed rotatably on the bottom wall of thewet-processing chamber 31 with its upper end projecting into thewet-processing chamber 31 and with its lower end projecting outside thewet-processing chamber 31 in such a manner as to keep air-tightness andwater-tightness inside the wet-processing chamber 31 in this case. Thelower end of the support shaft 33 is connected to a rotary shaft of amotor (not shown) as rotation driving means, for example.

The sample table 32 has a sample disposition surface on its surface. Thesample table 32 is disposed substantially horizontally at the upper endof the support shaft 33 with the sample disposition surface being itsupper surface. The sample disposition surface of the sample table 32 ispositioned below a sample scooping member 62 of an arm 61.

The sample table 32 is equipped with a sample delivery member (notshown). The sample delivery member is disposed movably up and downbetween a position below the sample disposition surface of the sampletable 32 and a position above the sample scooping member 62 of the arm61. A processing liquid feed pipe (not shown) is disposed inside thewet-processing chamber 31 in such a manner as to be capable of supplyinga processing solution to the sample disposition surface of the sampletable 32. A processing solution feed apparatus (not shown) is disposedoutside the wet-processing chamber 31. The processing solution feed pipeis connected to this processing solution feed apparatus. A waste liquordischarge pipe (not shown) is connected to the wet-processing chamber31. In this case, inert gas introduction means (not shown) forintroducing an inert gas such as nitrogen gas into the wet-processingchamber 31 are provided.

In FIGS. 2 and 3, the arm 61 is disposed rotatably so as to correspondto the sample tables 130 and 32. The arm 61 can rotate on the same planeoutside the buffer chamber 100. The sample scooping member 62 isdisposed at the rotating end of the arm 61. The planar shape of thesample scooping member 62 is substantially the same as those of thesample scooping members 52 and 82. The arm 61 is disposed in such amanner that the orbit of rotation of the center of the sample scoopingmember 62 corresponds substantially to the centers of the sample tables130 and 32, respectively. In other words, the support point of rotationof the arm 61 is positioned to a position where almost the center of thesample scooping member 62 describes the orbit of rotation describedabove.

The support point of rotation of the arm 61 is disposed at the upper endof the rotary shaft 63 disposed rotatably outside the buffer chamber 100and outside the wet-processing chamber 31. The lower end of the rotaryshaft 63 is connected to the driving shaft of a motor 64 for example, asrotation driving means. An opening 34 is bored on the side wall of thewet-processing chamber 31 that corresponds to the rotation zones of thearm 61 and sample scooping member 62. The size and position of theopening 34 are such that they do not prevent the entry and exitoperations of the arm 61 and sample scooping member 62 with respect tothe wet-processing chamber 31. The opening 34 can be opened and closedby switch means (not shown) in this case.

A sample table 42 is disposed inside the dry-processing chamber 41. Thesample table 42 has a sample disposition surface on its surface. It isdisposed substantially horizontally on the bottom wall of thedry-processing chamber 41. A heater 43 is used as heating means in thiscase. The heater 43 is disposed on the back of the sample table 42 insuch a manner as to be capable of heating the sample table 42. It isconnected to a power source (not shown).

The sample disposition surface of the sample table 42 is positionedbelow a sample scooping member 72 of an arm 71. A sample delivery member(not shown) is disposed on the sample table 42. In other words, thesample delivery member is disposed movably up and down between aposition below the sample disposition surface of the sample table 42 anda position above the sample scooping member 72 of the arm 71. In thiscase, the sample delivery member, too, is capable of moving up and downbetween a position below the sample disposition surface of the sampletable 32 and a position above the sample scooping member 72 of the arm71. In this case, there is provided inert gas introduction means (notshown) for introducing an inert gas such as nitrogen gas into thedry-processing chamber 41.

A cassette table 151 is disposed inside a sample recovery chamber 150.An elevation shaft 152 is disposed movably up and down on the bottomwall of the sample recovery chamber 150 with its upper end projectinginto the sample recovery chamber and with its lower end projectingoutside the sample recovery chamber 150. The cassette table 151 isdisposed substantially horizontally at the upper end of the elevationshaft 152 with a cassette disposition surface being its upper surface.The lower end of the elevation shaft 152 is disposed on elevationdriving means 153. In this case, inert gas introduction means (notshown) are arranged so as to introduce an inert gas such as nitrogen gasinto the sample recovery chamber 150.

In FIG. 2, a guide 73 is disposed along the inner wall surface of eachof the wet-processing chamber 31, the dry-processing chamber 41 and thesample recovery chamber 150. The guide 73 has a linear shape. In otherwords, the line passing through the centers of the sample tables 32, 42and the cassette table 151 is a straight line and the guide 73 isdisposed substantially parallel to this line. The arm 71 is a linearmember in this case and one of its ends is disposed on the guide 73 soas to be capable of reciprocation while being guided by the guide 73. Asample scooping member 72 is disposed at the other end of the arm 71.

Openings (not shown) are formed on the side walls of the wet- anddry-processing chambers 31, 41 and the sample recovery chamber 150corresponding to the reciprocation zones of the arm 71 and the samplescooping member 72, respectively, so that the arm 71 and the samplescooping member 72 are not prevented from coming into and out from thewet-processing chamber 31, the dry-processing chamber 41 and the samplerecovery chamber 150, respectively. These openings can be opened andclosed by switch means (not shown), respectively. An opening for loadingand discharging a cassette and a door (not shown) are disposed in thesample recovery chamber 150.

A cassette 160 is disposed on a cassette table 140. It can store aplurality of samples 170 one by one stacked in the longitudinaldirection, and one of its side surfaces is open in order to take out thesamples 170 from the cassette 160. The cassette 160 is disposed on thecassette table 140 with its sample take-out side surface facing theopening 101a. The cassette table 140 supporting the cassette 160 thereonis moved down, for example, under this state. Descent of the cassettetable 140 is stopped at the position where the sample 170 stored at theuppermost stage of the cassette 160 can be scooped up by the samplescooping member 143.

The operation of this apparatus is as follows:

The openings 101a and 101d are closed by the sample tables 110 and 130,respectively, and when an evacuation apparatus is operated under thisstate, the inside of the buffer chamber 100 is evacuated to apredetermined pressure. Thereafter, the cover member 111 is moved up andthis ascent is stopped at the position where the sample scooping member143 for scooping up the sample 170 is not prevented from reaching theopening 101a. The arm 142 is moved towards the cassette 160 under thisstate and this movement is stopped at the position where the samplescooping member 143 corresponds to the back of the sample 170 stored atthe lowermost stage of the cassette 160, for example. Thereafter thecassette 160 is moved up by the distance at which the sample scoopingmember 143 can scoop up the sample 170. In this manner the sample 170 isscooped up on its back by the sample scooping member 143 and deliveredto the sample scooping member 143.

When the sample scooping member 143 receives the sample 170, the arm 142is moved towards the opening 101a. This movement of the arm 142 isstopped at the point where the sample scooping member 143 having thesample 170 reaches the position corresponding to the opening 101a. Underthis state the sample delivery member of the sample table 110 is movedup so that the sample 170 is delivered from the sample scooping member143 to the sample delivery member. Thereafter, the sample scoopingmember 143 is retreated to the position at which it does not preventdescent of the sample delivery member receiving the sample 170 by themovement of the arm 142.

Thereafter the sample delivery member having the sample 170 is moveddown and the sample 170 is delivered from the sample delivery member tothe sample table 110 and placed on its sample disposition surface. Then,the cover member 111 is moved down. Accordingly, the opening 101a isclosed by the cover member 111 and its communication with the outside iscut off. Thereafter, the sample table 110 having the sample 170 is moveddown and this downward movement is stopped at the point where the sampletable 110 reaches the position at which the sample 170 can be exchangedbetween the sample delivery member of the sample table 110 and thesample scooping member 82 of the arm 81.

The flange 121 and the metallic bellows 122 are moved down by the shaft122a lest they prevent the rotation of the arm 81 and the samplescooping member 82 and the sample table 15 is moved down to the positionwhere its sample delivery member 15a and the sample scooping member 82of the arm 81 can exchange the sample 170 between them. Under this statethe sample delivery member 15a is moved up so that it can exchange thesample 170 with the sample scooping member 82 of the arm 81. The arm 81is then rotated in the direction of the sample table 110 and the samplescooping member 82 is located at the position which corresponds to theback of the sample 170 held by the sample delivery member of the sampletable 110 and at which it can scoop up the sample 170. Under this statethe sample delivery member of the sample table 110 is moved down and thesample 170 is delivered to the sample scooping member 82 of the arm 81.After scooping up the sample 170, the sample scooping member 82 isrotated in the direction of the sample table 15 while passing betweenthe flange 121 and the inner surface of the top wall of the bufferchamber 100 as the arm 81 is rotated in the direction of the sampletable 15.

The sample table 110 is moved up once again so that the opening 101a isclosed by the sample table 110. The rotation of the sample scoopingmember 82 described above is stopped when the sample scooping member 82reaches the position where the sample 170 can be exchanged between thesample scooping member 82 and the sample delivery member 15a of thesample table 15. The sample delivery member 15a of the sample table 15is moved up under this stage so that the sample 170 is delivered fromthe sample scooping member 82 t the sample delivery member 15a of thesample table 15. Thereafter, when the arm 81 is rotated to the positionbetween the openings 101a and 101b, the sample scooping member 82 isbrought into the stand-by state to prepare for the next delivery of thesample between the sample tables 110 and 15.

Thereafter the flange 121 and the metallic bellows 122 are moved up bythe shaft 122a so that communication of the buffer chamber 100 in themetallic bellows 122 and the inside of the discharge tube 11 with theinterior of the buffer chamber 100 outside the metallic bellows 122 iscut off. When the sample delivery member 15a of the sample table 15receiving the sample 170 is moved down, the sample 170 is delivered fromthe sample delivery member 15a of the sample table 15 to the sampletable 15 and is placed on the sample disposition surface of the sampletable 15. After receiving the sample 170 on its sample dispositionsurface, the sample table 15 is moved up to a predetermined position(see FIG. 5A) inside the space where communication with the bufferchamber 100 outside the metallic bellows 122 is cut off.

A predetermined processing gas is introduced at a predetermined flowrate from the processing gas source into the space in whichcommunication with the buffer chamber 100 outside the metallic bellows122 is cut off. Part of the processing gas introduced into this space isexhausted outside the space due to the operations of the evacuationapparatus and the variable resistance valve. In this manner the pressureof this space is controlled to a predetermined pressure for etchingtreatment.

The magnetron 13 oscillates a 2.45 GHz microwave in this case. Themicrowave thus oscillated propagate through the waveguides 12b and 12athrough the isolator 12c and the power monitor 12d and is absorbed bythe discharge tube 11, thereby generating a radio frequency fieldcontaining the microwave. At the same time, the solenoid coil 14 isoperated to generate a magnetic field. The processing gas existinginside the space where communication with the buffer chamber 100 outsidethe metallic bellows 122 is cut off is converted to plasma due to thesynergistic operations of the radio frequency field containing themicrowave and the magnetic field. The sample 170 disposed on the sampletable 15 is etched by utilizing this plasma.

Thereafter the sample table 15 and the flange 121 are moved downwardly(FIG. 5B) and the sample delivery member 15a is moved upwardly.

The rotation of the sample scooping member 52 is stopped a the pointwhen the sample scooping member 52 reaches the position where the etchedsample 170 can be exchanged between the sample scooping member 52 andthe sample delivery member 15a of the sample table 15. The sampledelivery member 15a of the sample table 15 is moved down under thisstate and the etched sample 170 is delivered from the sample deliverymember 15a of the sample table 15 to the sample scooping member 52 ofthe arm 51. After scooping up the etched sample 170, the sample scoopingmember 52 is rotated in the direction of the sample table 22 whilepassing between the flange 121 and the inner surface of the top wall ofthe buffer chamber 100 as the arm 51 is rotated in the direction of thesample table 22.

A new sample in the cassette 160 is placed by the operations describedabove on the sample table 15 from which the etched sample 170 isremoved. The new sample placed on the sample table 15 is subsequentlyetch-processed due to the operations described above.

Before, or during, the rotation of the sample scooping member 52 havingthe etched sample 170, the flange 126 and the metallic bellows 127 aremoved down lest they prevent the rotation of the arm 51 and the samplescooping member 52. The radio frequency power source 18 is operated atthe time of etching of the sample 170, a predetermined radio frequencypower is applied to the sample table 15 through the elevation shaft 16and a predetermined radio frequency bias is applied to the sample 170.The sample 170 is adjusted to a predetermined temperature through thesample table 15.

The operations of the magnetron 13, solenoid coil 14 and radio frequencypower source 18, and the like, are stopped at the point where etching ofthe sample 170 is complete and introduction of the processing gas intothe space whose communication with the inside of the buffer chamber 100outside the metallic bellows 122 is cut off is stopped. After evacuationof this space is conducted sufficiently, the switch valve constitutingthe evacuation means is closed. Thereafter, the flange 121 and themetallic bellows 122 are moved down so as not to prevent the rotation ofthe arm 51 and the sample scooping member 52 and the sample table 15 ismoved down to the position where its sample delivery member and thesample scooping member 52 of the arm 51 can exchange the etched sample170. The sample delivery member of the sample table 15 is then moved upso that it can exchange the etched sample 170 with the sample scoopingmember 52 of the arm 51. When the arm 51 is rotated under this state inthe direction of the sample table 15, the sample scooping member 52passes between the flange 121 and the inner surface of the top wall ofthe buffer chamber 100 and is rotated in the direction of the sampletable 15.

The sample scooping member 52 having the etched sample 170 is rotated inthe direction of the sample table 22 while passing between the flange126 and the inner surface of the top wall of the buffer chamber 100 whenthe arm 51 is rotated further in the direction of the sample table 22.Such a rotation of the sample scooping member 52 is stopped when thesample scooping member 52 reaches the position where the etched sample170 can be exchanged between the sample scooping member 52 and thesample delivery member of the sample table 22. The sample deliverymember of the sample table 22 is moved up under this state and theetched sample 170 is delivered from the sample scooping member 52 to thesample delivery member of the sample table 22. Thereafter the samplescooping member 52 is rotated to the position between the openings 101cand 101d and is brought into the stand-by state.

Thereafter, the flange 126 and the metallic bellows 127 are moved up andthe interior of the buffer chamber 100 inside the metallic bellows 127and the interior of the plasma post-processing chamber 21 are cut offfrom communication with the interior of the buffer chamber 100 outsidethe metallic bellows 127. When the sample delivery member of the sampletable 22 receiving the etched sample 170 is moved down, the etchedsample 170 is delivered from the sample delivery member of the sampletable 22 to the sample table 22 and is placed on the sample dispositionsurface of the sample table 22.

The post-processing gas is introduced at a predetermined flow rate intothe space whose communication with the interior of the buffer chamber100 outside the metallic bellows 127 is cut off, and part of thepost-processing gas is exhausted from this space. In this manner thepressure of this space is adjusted to a predetermined post-processingpressure. Thereafter, the post-processing gas existing in this space isconverted in this case to plasma due to the operation of the radiofrequency field containing a microwave. The etched sample 170 placed onthe sample table 22 is post-processed by utilizing this plasma.

After the post-processing of the etched sample is thus complete,introduction of the post-processing gas into the space, which is cut offfrom the interior of the buffer chamber 100 outside the metallic bellows127, and conversion to plasma of the post-processing gas are stopped.Then, the flange 126 and the metallic bellows 127 are moved down lestthey prevent the rotation of the arm 51 and the sample scooping member52.

The sample scooping member 52 that is under the stand-by state betweenthe openings 101c and 101d is rotated to the position which does notprevent the rise of the post-processed sample 170 on the sample table 22and which has passed the sample table 22. The sample delivery member ofthe sample table 22 is moved up under this state so that thepost-processed sample 170 placed on the sample table 22 is delivered tothe sample delivery member of the sample table 22. Then, when the arm 51is rotated in the direction of the sample table 22, the sample scoopingmember 52 is located to the position at which it can scoop up the sample170, so as to correspond to the back of the post-processed sample 170held by the sample delivery member of the sample table 22. The sampledelivery member of the sample table 22 is moved down under this stateand the post-processed sample 170 is delivered from the sample deliverymember of the sample table 22 to the sample scooping member 52 of thearm 51.

After receiving the post-processed sample 170, the sample scoopingmember 52 is rotated in the direction of the sample table 130 whilepassing between the flange 126 and the inner surface of the top wall ofthe buffer chamber 100 when the arm 51 is rotated in the direction ofthe sample table 130. After the post-processed sample 170 is removed,the next etched sample is placed on the sample table 22 and is thenpost-processed by utilizing plasma.

Before, or during, the rotation of the sample scooping member 52 havingthe post-processed sample 170 as described above, the sample table 130is moved down to the position at which its sample delivery member 130aand the sample scooping member 52 of the arm 51 can exchange thepost-processed sample 170. The rotation of the sample scooping member 52is stopped when it reaches the position at which the post-processedsample 170 can be exchanged between the sample scooping member 52 andthe sample delivery member 130a of the sample table 130 (FIG. 4A). Thesample delivery member 130a of the sample table 130 is moved up underthis state so that the post-processed sample 170 is delivered from thesample scooping member 52 to the sample delivery member 130a of thesample table 130 (FIG. 4B).

Thereafter, when the arm 51 is rotated to the position between theopenings 101b and 101c, the sample scooping member 52 is brought intothe stand-by state at that position in order to transfer the next etchedsample to the sample table 22.

After receiving the post-processed sample 170, the sample deliverymember 130a of the sample moved down. Accordingly, the post-processedsample 170 is delivered from the sample delivery member 130a of thesample table 130 to the sample table 130 and placed on its sampledisposition surface (FIG. 4C). The sample table 130 having thepost-processed sample 170 is moved up so that the opening 101d is closedair-tight by the sample table 130 (FIG. 4D). The cover member 131 ismoved up under this state. The rise of the cover member 131 is stoppedwhen it reaches the position (FIG. 4E) at which the rise of the sampledelivery member 130a of the sample table 130 is not prevented andmoreover, the sample scooping member 62 of the arm 61 is not preventedfrom reaching the position where it can receive the post-processedsample 170 from the sample delivery member 130a of the sample table 130.Under this stage, the sample delivery member 130a of the sample table130 is first moved up. Accordingly, the post-processed sample 170 isdelivered from the sample table 130 to its sample delivery member 130a(FIG. 4F).

Next, when the arm 61 is rotated in the direction of the sample table130, the sample scooping member 62 is rotated in the direction of thesample table 130. This rotation of the sample scooping member 62 isstopped when it reaches the position where the post-processed sample 170can be exchanged between it and the sample delivery member 130a of thesample table 130 or in other words, the position which corresponds tothe back of the post-processed sample 170 held by the sample deliverymember 130a of the sample table 130 (FIG. 4G). The sample deliverymember 130a of the sample table 130 is then moved down so that thepost-processed sample 170 is delivered from the sample delivery member130a of the sample table 130 to the sample scooping member 62. Afterreceiving the post-processed sample 170, the sample scooping member 62is rotated towards the sample table 32 inside the wet-processing chamber31 when the arm 61 is rotated in the direction of the wet-processingchamber 31.

After delivering the post-processed sample 170 to the sample scoopingmember 62, the sample delivery member 130a of the sample table 130 isfurther moved down to the position which is below the sample dispositionsurface of the sample table 130. The cover member 131 is thereaftermoved down and the opening 101d is closed air-tight by the cover member131. The sample table 130 is again moved down under this state and thenext post-processed sample is delivered to and placed on this sampletable 130.

The rotation of the sample scooping member 62 having the post-processedsample 170 is stopped when it reaches the position at which it canexchange the post-processed sample 170 between it and the sampledelivery member of the sample table 32. The sample delivery member ofthe sample table 32 is moved up under this state. Accordingly, thepost-processed sample 170 is delivered from the sample scooping member62 to the sample delivery member of the sample table 32. Afterdelivering the post-processed sample 170, the sample scooping member 62is moved outside the wet-processing chamber 31 in order to prepare foracceptance of the next post-processed sample. The opening 34 is thenclosed.

The sample delivery member of the sample table 32 is moved down afterreceiving the post-processed sample 170. Accordingly, the post-processedsample 170 is delivered from the sample delivery member of the sampletable 32 to the sample table 32 and is placed on its sample dispositionsurface. The processing solution is then supplied at a predeterminedflow rate from the processing solution feed apparatus to the processedsurface of the post-processed sample 170 placed on the sample table 32through the processing solution feed pipe. At the same time, thepost-processed sample 170 is rotated by the operation of the motor. Inthis manner, wet-processing of the post-processed sample 170 isexecuted.

Nitrogen gas, for example, is introduced into the wet-processing chamber31 by the inert gas introduction means so that wet-processing is carriedout in the nitrogen gas atmosphere. The waste liquor generated by thiswet-processing is discharged outside the wet-processing chamber 31through the waste liquor discharge pipe.

After such a wet-processing is complete, the supply of the processingsolution, the rotation of the sample 170, and the like, are stopped, andthe sample delivery member of the sample table 32 is moved up. Duringthis rise, the wet-processed sample 170 is delivered from the sampletable 32 to its sample delivery member. The rise of the sample deliverymember receiving the wet-processed sample 170 is stopped at the positionwhere this sample 170 can be exchanged between the sample deliverymember and the sample scooping member 72. The sample scooping member 72is moved under this state towards the sample table 32. This movement isstopped when the sample scooping member 72 reaches the position wherethe wet-processed sample 170 can be exchanged between the samplescooping member 72 and the sample delivery member of the sample table32. The sample delivery member of the sample table 32 is then moveddown. Accordingly, the wet-processed sample 170 is delivered to thesample scooping member 72. After the wet-processed sample 170 isremoved, the sample delivery member of the sample table 32 prepares forthe acceptance of the next post-processed sample.

The sample scooping member 72 having the wet-processed sample 170 isfurther moved to the dry-processing chamber 41 from the wet-processingchamber 31 passing through the opening towards the sample table 42through the arm 71. This movement is stopped when the sample scoopingmember 72 reaches the position at which the wet-processed sample 170 canbe exchanged between the sample scooping member 72 and the sampledelivery member of the sample table 42. The sample delivery member ofthe sample table 42 is then moved up. Accordingly, the wet-processedsample 170 is delivered to the sample delivery member of the sampletable 42. After the wet-processed sample 170 is removed, the samplescooping member 72 is once moved back and the sample delivery member ofthe sample table 42 is moved down. Accordingly, the wet-processed sample170 is delivered from the sample delivery member of the sample table 42to the sample table 42 and is placed on its sample disposition surface.

The sample table 42 is heated externally by supply of power to theheater 43 and the wet-processed sample 170 is heated through the sampletable 42. The temperature of the wet-processed sample 170 is controlledto a predetermined temperature by adjusting the feed quantity to theheater 43. Thus the wet-processed sample 170 is dry-processed. Nitrogengas, for example, is introduced into the dry-processing chamber 41 bythe inert gas introduction means and dry-processing is carried out inthe nitrogen gas atmosphere.

After dry-processing is thus complete, the sample delivery member of thesample table 42 is moved up. During this rise, the dry-processed sample170 is delivered from the sample table 42 to its sample delivery member.The rise of the sample delivery member of the sample table 42 receivingthe dry-processed sample 170 is stopped when the dry-processed sample170 can be exchanged between it and the sample scooping member 72. Underthis state, the sample scooping member 72 is again moved towards thesample table 42 through the arm 71. This movement is stopped when thesample scooping member 72 reaches the position at which thedry-processed sample 170 can be delivered between the sample scoopingmember 72 and the sample delivery member of the sample table 42. Thesample delivery member of the sample table 42 is then moved down.Accordingly, the dry-processed sample is transferred to the samplescooping member 72. The sample delivery member of the sample table 42from which the dry-processed sample 170 is removed prepares foracceptance of the next wet-processed sample.

The sample scooping member 72 having the dry-processed sample 170 isfurther moved from the dry-processing chamber 41 to the sample recoverychamber 150 through the opening towards the cassette table 151 throughthe arm 71. This movement is stopped when the sample scooping member 72reaches the position where the dry-processed sample 170 can be deliveredbetween it and the cassette 161 placed on the cassette table 151.

The cassette 161 has a plurality of storage grooves in the direction ofheight, for example, and is positioned so that the uppermost groove canaccept and store the sample. The cassette 161 is intermittently moveddown by a predetermined distance under this state. Accordingly, thedry-processed sample is supported by the uppermost groove of thecassette 161 and is recovered and stored therein.

Nitrogen gas, for example, is introduced into the sample recoverychamber 150 by the inert gas introduction means so that thedry-processed sample 170 is stored in the nitrogen gas atmosphere and isonce preserved in the sample recovery chamber 150. Recovery of thedry-processed samples into the cassette 161 is sequentially conductedand after this recovery is complete, the cassette 161 is dischargedoutside the sample recovery chamber 150. The sample thus taken out fromthe sample recovery chamber 150 while stored in the cassette 161 istransferred to the next step.

EXAMPLE

The following sample is prepared several times. First, a 3,000 Å-thicksilicon dioxide film 172 is formed on a Si substrate 171 such as shownin FIG. 6, a laminate wiring of a TiW layer 173 and an Al-Cu-Si film 174is formed on the former and a photoresist 175 is used as a mask. Thissample is processed by use of the apparatus shown in FIGS. 2-3, 4A-4Gand 5A-5B.

The etching conditions are BCl₃ +Cl₂ as the processing gas, with a flowrate of the processing gas of 150 sccm (standard cm³ per minute), aprocessing pressure of 16 mTorr, a microwave output of 600 W and aradio-frequency bias of 60 W.

The samples which are passed through all the subsequent steps withoutany processing after etching are referred to as (A), those which areetched, plasma post-processed but are not passed through the wet- anddry-processings are referred to as (B), those which are subjected to thepredetermined processings at all the steps are referred to as (D) andthose which are not plasma post-processed after etching but are wet- anddry-processed are referred to as (C). The corrosion-proofing effects ofthese samples are then compared.

The processing conditions in the plasma post-processing chamber are O₂+CF₄ as the processing gas, with a flow rate of the processing gas of400 sccm (O₂) and 35 sccm (CF₄) and a processing pressure of 1.5 Torr,and the plasma is generated by use of a 2.45 GHz microwave. In thiscase, the plasma post-processing is mainly intended to ash (remove) thephotoresist and to remove chlorides remaining on the protective film onthe pattern sidewall and the pattern bottom portion, and ashing isconducted for about 30 seconds and additional processing under the samecondition is conducted for about one minute. In wet-processing, spinningwater wash treatment with pure water is conducted for one minute andspinning drying is conducted for 30 seconds. Furthermore, the sampletable is heated to 150° C. in the nitrogen gas atmosphere and thewet-processed sample is left standing for the minute for dry-processing.

When those samples (B) which are etched and then plasma post-processedbut are not passed through the wet-processing, that is, water washingtreatment and dry-processing, are observed through an opticalmicroscope, spot-like matters analogous to corrosion can be observedwithin about one hour. Accordingly, they are observed in further detailby SEM. Fan-like corrosion products 180 starting from the boundarybetween the TiW layer and the Al-Cu-Si layer are observed as shown inFIG. 7. Even though the mixing ratio of CF₄ with respect to O₂ ischanged to from 5 to 20%, the processing pressure is changed to from 0.6to 2 Torr and the sample temperature is raised to 250° C., corrosionanalogous to that described above is observed within a few hours in eachcase.

It is therefore believed that particularly in a laminate layer wiring,or alloy wiring, containing different kinds of metals having mutuallydifferent ionization potentials, corrosion is generated and acceleratedby so-called electrolytic corrosion due to battery operation.

To sufficiently prevent the occurrence of such corrosion, it has beenfound that plasma post-processing alone after etching is not sufficientand even limited amounts of chlorine components must be removedcompletely.

As described above, therefore, processing was carried out under variousconditions to examine the time till the occurrence of corrosion afterprocessing. The result is shown in FIG. 8.

As can be seen from FIG. 8, in the case of wiring materials such as thelaminate layer wiring in which corrosion is vigorous, the plasmapost-processing such as resist ashing after etching, or water washingprocessing and drying processing after etching without carrying outplasma post-processing cannot provide a sufficient corrosion-proofingeffect. A high corrosion-proofing effect for more than 30 hours can onlybe obtained by carrying out in series the etch-processing, the plasmapost-processing such as ashing of the resist, the water washingprocessing and the dry-processing.

Besides the washing process described above, the same effect ofinhibition of corrosion can be obtained by passivation processing with amixture of nitric acid and hydrogen fluoride or nitric acid, which alsoserves to remove any residues after plasma etching, before the waterwashing processing.

In order to remove the reactive products on the pattern sidewall thatcannot be removed sufficiently by the plasma post-processing, it isadvisable to conduct liquid processing by use of a weakly alkalinesolution or a weakly acidic solution (e.g. acetic acid) after plasmapost-processing subsequent to etching and then to carry out the waterwashing processing and dry-processing. In this manner, the chlorinecomponents can be removed more completely and the corrosion-proofingeffect can be further improved.

In the embodiment described above, the time till completion of thewet-processing of the plasma post-processed sample is limited to aboutone hour because corrosion occurs within about one hour as shown in FIG.8 in the case of the sample shown in FIG. 6. However, wet-processing ispreferably completely as quickly as possible. In other words, the plasmapost-processed sample is preferably transferred immediately aftercompletion of plasma post-processing from the plasma post-processingapparatus to the wet-processing apparatus. Though the plasmapost-processed sample is transferred inside the atmosphere in theembodiment described above, it may be transferred in a vacuum or in aninert gas atmosphere. Transfer in such an atmosphere is extremelyeffective when the time from plasma post-processing till the start ofwet-processing is longer than the corrosion occurrence time in theatmosphere, for example. In such a case, means may be disposed betweenthe plasma post-processing apparatus and wet-processing apparatus forpreserving the plasma post-processed sample in A vacuum or in the inertgas atmosphere.

FIG. 9 explains a second embodiment of the present invention. Thedifference of this embodiment from the first embodiment shown in FIG. 1lies in that a passivation-processing apparatus 190 is additionallydisposed on the downstream side of the dry-processing apparatus 40. Inthis case, the sample transfer means 90 has the function of transferringthe dry-processed sample from the dry-processing chamber (not shown) ofthe dry-processing apparatus to a passivation-processing chamber (notshown) of the passivation-processing apparatus 190. Additionally, sampletransfer means 200 for transferring the passivated sample to a recoverycassette (not shown), for example, is disposed. Like reference numeralsare used to identify like constituents as in FIG. 1 and theirexplanation will be omitted.

In FIG. 9, the etched, plasma post-processed sample (not shown) istransferred into the wet-processing chamber (not shown) of thewet-processing apparatus 30 by the sample transfer means 60 and isplaced on the sample disposition surface of the sample table (not shown)as the wet-processing station inside the wet-processing chamber. Theplasma post-processed sample placed on the sample table in thewet-processing chamber is subjected to development solution processing.Residues, and the reactive products on the pattern sidewall, afteretching are completely removed by such wet-processing. If the samplecontains Al as its component, Al, too, is partly dissolved. When such asample is dry-processed and taken out into the atmosphere, for example,oxidation as a form of corrosion will occur disadvantageously.Therefore, the sample subjected to development and dry-processed in thedry-processing chamber of the dry-processing apparatus 40 is transferredinto the passivation-processing chamber of the passivation-processingapparatus 190 and is placed on the sample disposition surface of thesample table (not shown) as the processing station in thepassivation-processing apparatus 190. Gas plasma forpassivation-processing or oxygen gas plasma in this case is generated inor introduced into the passivation-processing chamber. Ozone may be usedinstead of oxygen. The dry-processed sample placed on the sample tablein the passivation-processing chamber is passivation-processed by theoxygen gas plasma. The passivation-processed sample is transferred fromthe passivation-processing chamber to the recovery cassette by thesample transfer means and recovered and stored therein.

Passivation-processing may use nitric acid, besides the chemicalsdescribed above.

Since the present invention can sufficiently remove the corrosivematerials generated by etching of the sample, it provides the effectthat corrosion of the sample after etching can be prevented sufficientlyirrespective of the type of sample.

We claim:
 1. A method of processing a sample comprising the steps of:(i)etching the sample by means of a first plasma formed in a gasatmosphere, (ii) after step (i), treating the sample by means of asecond plasma to remove residual corrosive compounds formed in step (i),said second plasma being formed in a gas atmosphere different from thegas atmosphere in which the first plasma is formed, (iii) contacting asurface of said sample etched in step (i) and treated in step (ii) withat least one liquid which effects at least one of (a) removal ofresidual corrosive compounds formed in step (i) which were not removedin step (ii) and (b) passivation of said surface etched in step (i) andtreated in step (ii), and (iv) after step (iii), drying the sample.
 2. Amethod according to claim 1 wherein the first plasma is formed in a gasatmosphere which comprises a chlorine-containing gas.
 3. A methodaccording to claim 1 wherein in step (i) the etching is performedthrough a mask on said sample.
 4. A method according to claim 3 whereinsaid plasma treatment of step is performed so as to effect removal of atleast part of said mask.
 5. A method according to claim 1 wherein step(ii) is performed in a different chamber from step (i).
 6. A methodaccording to claim 1 wherein said second plasma of step (ii) is formedin a gas atmosphere comprising oxygen.
 7. A method according to claim 1wherein step (iii) comprises washing to effect removal of residualcorrosive compounds formed in step (i) which were not removed in step(ii), said washing being selected from the group consisting of(a)washing with water, (b) washing with an alkaline liquid and thereafterwith water, (c) washing with an acidic liquid and thereafter with water,and (d) washing with a mixture of nitric acid and hydrofluoric acid andthereafter with water.
 8. A method according to claim 1 wherein step(iii) comprises passivation of said surface effected by one of (a) amixture of nitric acid and hydrogen fluoride and (b) nitric acid.
 9. Amethod according to claim 1 wherein said step (iii) is performed in aninert gas atmosphere.
 10. A method according to claim 1 wherein saidstep (iv) is performed in an inert gas atmosphere.
 11. A methodaccording to claim 1 further comprising the step of subjecting saidsample to passivation of said surface after step (iv).
 12. A methodaccording to claim 1 wherein said sample comprises a substrate and onsaid substrate a layer which is subjected to the etching of step (i),said layer being selected from the group consisting of (a) a laminatecomprising metals of different ionization potentials and (b) an alloy ofmetals of different ionization potentials.
 13. A method according toclaim 1 wherein said sample comprises a substrate and on said substratea layer which is etched in step (i), said layer being made from filmsmade of Al, Cu, W, Ti, Mo, other refractory metals, alloys of Al, Cu, W,Ti, Mo and other refractory metals, alloys of Al, Cu, W, Ti, Mo andother refractory metals containing silicon, silicides of refractorymetals, TiN and TiW, and laminates of at least two such films.
 14. Amethod of substantially freeing a plasma-etched sample of residualcorrosive compounds produced when the sample was etched, comprising thesteps of:(i) treating a plasma-etched surface of the sample by means ofa plasma which removed from said surface residual corrosive compoundsproduced when the sample was plasma etched, (ii) washing the surface ofsaid sample treated in step (i) with a liquid which removes residualcorrosive compounds formed when the sample was etched which were notremoved in step (i), and (iii) drying said sample after step (ii).